<?php

/*
	Question2Answer (c) Gideon Greenspan

	http://www.question2answer.org/

	
	File: qa-include/qa-db-points.php
	Version: See define()s at top of qa-include/qa-base.php
	Description: Database-level access to user points and statistics


	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	More about this license: http://www.question2answer.org/license.php
*/

if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
    header('Location: ../');
    exit;
}


function qa_db_points_option_names()
    /*
        Returns an array of option names required to perform calculations in userpoints table
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    return array(
        'points_post_q', 'points_select_a', 'points_per_q_voted_up', 'points_per_q_voted_down', 'points_q_voted_max_gain', 'points_q_voted_max_loss',
        'points_post_a', 'points_a_selected', 'points_per_a_voted_up', 'points_per_a_voted_down', 'points_a_voted_max_gain', 'points_a_voted_max_loss',
        'points_vote_up_q', 'points_vote_down_q', 'points_vote_up_a', 'points_vote_down_a',

        'points_multiple', 'points_base',
    );
}


function qa_db_points_calculations()
    /*
        Returns an array containing all the calculation formulae for the userpoints table. Each element of this
        array is for one column - the key contains the column name, and the value is a further array of two elements.
        The element 'formula' contains the SQL fragment that calculates the columns value for one or more users,
        where the ~ symbol within the fragment is substituted for a constraint on which users we are interested in.
        The element 'multiple' specifies what to multiply each column by to create the final sum in the points column.
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    require_once QA_INCLUDE_DIR . 'qa-app-options.php';

    $options = qa_get_options(qa_db_points_option_names());

    return array(
        'qposts' => array(
            'multiple' => $options['points_multiple'] * $options['points_post_q'],
            'formula' => "COUNT(*) AS qposts FROM ^posts AS userid_src WHERE userid~ AND type='Q'",
        ),

        'aposts' => array(
            'multiple' => $options['points_multiple'] * $options['points_post_a'],
            'formula' => "COUNT(*) AS aposts FROM ^posts AS userid_src WHERE userid~ AND type='A'",
        ),

        'cposts' => array(
            'multiple' => 0,
            'formula' => "COUNT(*) AS cposts FROM ^posts AS userid_src WHERE userid~ AND type='C'",
        ),

        'aselects' => array(
            'multiple' => $options['points_multiple'] * $options['points_select_a'],
            'formula' => "COUNT(*) AS aselects FROM ^posts AS userid_src WHERE userid~ AND type='Q' AND selchildid IS NOT NULL",
        ),

        'aselecteds' => array(
            'multiple' => $options['points_multiple'] * $options['points_a_selected'],
            'formula' => "COUNT(*) AS aselecteds FROM ^posts AS userid_src JOIN ^posts AS questions ON questions.selchildid=userid_src.postid WHERE userid_src.userid~ AND userid_src.type='A' AND NOT (questions.userid<=>userid_src.userid)",
        ),

        'qupvotes' => array(
            'multiple' => $options['points_multiple'] * $options['points_vote_up_q'],
            'formula' => "COUNT(*) AS qupvotes FROM ^uservotes AS userid_src JOIN ^posts ON userid_src.postid=^posts.postid WHERE userid_src.userid~ AND LEFT(^posts.type, 1)='Q' AND userid_src.vote>0",
        ),

        'qdownvotes' => array(
            'multiple' => $options['points_multiple'] * $options['points_vote_down_q'],
            'formula' => "COUNT(*) AS qdownvotes FROM ^uservotes AS userid_src JOIN ^posts ON userid_src.postid=^posts.postid WHERE userid_src.userid~ AND LEFT(^posts.type, 1)='Q' AND userid_src.vote<0",
        ),

        'aupvotes' => array(
            'multiple' => $options['points_multiple'] * $options['points_vote_up_a'],
            'formula' => "COUNT(*) AS aupvotes FROM ^uservotes AS userid_src JOIN ^posts ON userid_src.postid=^posts.postid WHERE userid_src.userid~ AND LEFT(^posts.type, 1)='A' AND userid_src.vote>0",
        ),

        'adownvotes' => array(
            'multiple' => $options['points_multiple'] * $options['points_vote_down_a'],
            'formula' => "COUNT(*) AS adownvotes FROM ^uservotes AS userid_src JOIN ^posts ON userid_src.postid=^posts.postid WHERE userid_src.userid~ AND LEFT(^posts.type, 1)='A' AND userid_src.vote<0",
        ),

        'qvoteds' => array(
            'multiple' => $options['points_multiple'],
            'formula' => "COALESCE(SUM(" .
                "LEAST(" . ((int)$options['points_per_q_voted_up']) . "*upvotes," . ((int)$options['points_q_voted_max_gain']) . ")" .
                "-" .
                "LEAST(" . ((int)$options['points_per_q_voted_down']) . "*downvotes," . ((int)$options['points_q_voted_max_loss']) . ")" .
                "), 0) AS qvoteds FROM ^posts AS userid_src WHERE LEFT(type, 1)='Q' AND userid~",
        ),

        'avoteds' => array(
            'multiple' => $options['points_multiple'],
            'formula' => "COALESCE(SUM(" .
                "LEAST(" . ((int)$options['points_per_a_voted_up']) . "*upvotes," . ((int)$options['points_a_voted_max_gain']) . ")" .
                "-" .
                "LEAST(" . ((int)$options['points_per_a_voted_down']) . "*downvotes," . ((int)$options['points_a_voted_max_loss']) . ")" .
                "), 0) AS avoteds FROM ^posts AS userid_src WHERE LEFT(type, 1)='A' AND userid~",
        ),

        'upvoteds' => array(
            'multiple' => 0,
            'formula' => "COALESCE(SUM(upvotes), 0) AS upvoteds FROM ^posts AS userid_src WHERE userid~",
        ),

        'downvoteds' => array(
            'multiple' => 0,
            'formula' => "COALESCE(SUM(downvotes), 0) AS downvoteds FROM ^posts AS userid_src WHERE userid~",
        ),
    );
}


function qa_db_points_update_ifuser($userid, $columns)
    /*
        Update the userpoints table in the database for $userid and $columns, plus the summary points column.
        Set $columns to true for all, empty for none, an array for several, or a single value for one.
        This dynamically builds some fairly crazy looking SQL, but it works, and saves repeat calculations.
    */
{
    if (qa_to_override(__FUNCTION__)) {
        $args = func_get_args();
        return qa_call_override(__FUNCTION__, $args);
    }

    if (qa_should_update_counts() && isset($userid)) {
        require_once QA_INCLUDE_DIR . 'qa-app-options.php';

        $calculations = qa_db_points_calculations();

        if ($columns === true)
            $keycolumns = $calculations;
        elseif (empty($columns))
            $keycolumns = array(); elseif (is_array($columns))
            $keycolumns = array_flip($columns); else
            $keycolumns = array($columns => true);

        $insertfields = 'userid, ';
        $insertvalues = '$, ';
        $insertpoints = (int)qa_opt('points_base');

        $updates = '';
        $updatepoints = $insertpoints;

        foreach ($calculations as $field => $calculation) {
            $multiple = (int)$calculation['multiple'];

            if (isset($keycolumns[$field])) {
                $insertfields .= $field . ', ';
                $insertvalues .= '@_' . $field . ':=(SELECT ' . $calculation['formula'] . '), ';
                $updates .= $field . '=@_' . $field . ', ';
                $insertpoints .= '+(' . (int)$multiple . '*@_' . $field . ')';
            }

            $updatepoints .= '+(' . $multiple . '*' . (isset($keycolumns[$field]) ? '@_' : '') . $field . ')';
        }

        $query = 'INSERT INTO ^userpoints (' . $insertfields . 'points) VALUES (' . $insertvalues . $insertpoints . ') ' .
            'ON DUPLICATE KEY UPDATE ' . $updates . 'points=' . $updatepoints . '+bonus';

        qa_db_query_raw(str_replace('~', "='" . qa_db_escape_string($userid) . "'", qa_db_apply_sub($query, array($userid))));
        // build like this so that a #, $ or ^ character in the $userid (if external integration) isn't substituted

        if (qa_db_insert_on_duplicate_inserted())
            qa_db_userpointscount_update();
    }
}


function qa_db_points_set_bonus($userid, $bonus)
    /*
        Set the number of explicit bonus points for $userid to $bonus
    */
{
    qa_db_query_sub(
        "INSERT INTO ^userpoints (userid, bonus) VALUES ($, #) ON DUPLICATE KEY UPDATE bonus=#",
        $userid, $bonus, $bonus
    );
}


function qa_db_userpointscount_update()
    /*
        Update the cached count in the database of the number of rows in the userpoints table
    */
{
    if (qa_should_update_counts())
        qa_db_query_sub("REPLACE ^options (title, content) SELECT 'cache_userpointscount', COUNT(*) FROM ^userpoints");
}


/*
	Omit PHP closing tag to help avoid accidental output
*/